A framework to measure the properties of intergalactic metal systems with two-point flux statistics

Journal Article · 05 May 2023 · Monthly Notices of the Royal Astronomical Society

DOI: https://doi.org/10.1093/mnras/stad1363 · OSTI ID:1974304

Karaçaylı, Naim Göksel  ^[1]; Martini, Paul ^[1]; Weinberg, David H. ^[1]; Iršič, Vid ^[2]; Aguilar, J. ^[3]; Ahlen, S. ^[4]; Brooks, D. ^[5]; de la Macorra, A. ^[6]; Font-Ribera, A.  ^[7]; Gontcho A Gontcho, S.  ^[3]; Guy, J. ^[3]; Kisner, T. ^[3]; Miquel, R. ^[8]; Poppett, C. ^[9]; Ravoux, C.  ^[10]; Schubnell, M. ^[11]; Tarlé, G. ^[11]; Weaver, B. A. ^[12]; Zhou, Z. ^[13]

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1. The Ohio State University, Columbus, OH (United States)
2. University of Cambridge (United Kingdom)
3. Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
4. Boston University, MA (United States)
5. University College London (United Kingdom)
6. Universidad Nacional Autonoma de Mexico (UNAM), Mexico City (Mexico)
7. Barcelona Institute of Science and Technology (BIST) (Spain)
8. Barcelona Institute of Science and Technology (BIST) (Spain); Inst. Catalana de Recerca i Estudis Avancats (ICREA) (Spain)
9. Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); University of California, Berkeley, CA (United States)
10. Université Paris-Saclay, Gif-sur-Yvette (France)
11. University of Michigan, Ann Arbor, MI (United States)
12. National Optical-Infrared Astronomy Research Laboratory (NOIRLab), Tucson, AZ (United States)
13. Chinese Academy of Sciences (CAS), Beijing (China)

The abundance, temperature, and clustering of metals in the intergalactic medium are important parameters for understanding their cosmic evolution and quantifying their impact on cosmological analysis with the Ly α forest. The properties of these systems are typically measured from individual quasar spectra redward of the quasar’s Ly α emission line, yet that approach may provide biased results due to selection effects. Here, we present an alternative approach to measure these properties in an unbiased manner with the two-point statistics commonly employed to quantify large-scale structure. Our model treats the observed flux of a large sample of quasar spectra as a continuous field and describes the one-dimensional, two-point statistics of this field with three parameters per ion: the abundance (column density distribution), temperature (Doppler parameter), and clustering (cloud–cloud correlation function). We demonstrate this approach on multiple ions (e.g. $${\rm C\, \small {\rm IV}}$$ , $${\rm Si\, \small {\rm IV}}$$ , and $${\rm Mg\, \small {\rm II}}$$ ) with early data from the Dark Energy Spectroscopic Instrument (DESI) and high-resolution spectra from the literature. Our initial results show some evidence that the $${\rm C\, \small {\rm IV}}$$ abundance is higher than previous measurements and evidence for abundance evolution over time. The first full year of DESI observations will have over an order of magnitude more quasar spectra than this study. In a future paper, we will use those data to measure the growth of clustering and its impact on the Ly α forest, as well as test other DESI analysis infrastructure such as the pipeline noise estimates and the resolution matrix.

• Research Organization: The Ohio State University, Columbus, OH (United States); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); Univ. of Michigan, Ann Arbor, MI (United States)
• Sponsoring Organization: USDOE Office of Science (SC), High Energy Physics (HEP); USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities (SUF); USDOE
• Grant/Contract Number: SC0011726; AC02-05CH11231; SC0019193
• OSTI ID: 1974304
• Alternate ID(s): OSTI ID: 2216892; OSTI ID: 2356790; OSTI ID: 2368758
• Journal Information: Monthly Notices of the Royal Astronomical Society, Vol. 522, Issue 4; ISSN 0035-8711
• Publisher: Oxford University PressCopyright Statement
• Country of Publication: United States
• Language: English